Abstract: The present invention is an apparatus and method of encryption. A first table comprising a set of 2.sup.n distinct n-bit input numbers and a first set of 2.sup.n distinct n-bit output numbers is received. A second table comprising of the set of 2.sup.n distinct n-bit input numbers and a second set of 2.sup.n distinct n-bit output numbers is also received. The first and second sets of 2.sup.n n-bit output numbers are each a one-to-one mapping of the set of 2.sup.n n-bit input numbers, and the second mapping of 2.sup.n n-bit output numbers is disjoint from the first mapping of 2.sup.n n-bit output numbers. The first and the second tables are combined and a fourth table of 2.sup.n pairs of (n+1)-bit numbers is generated by converting each of the 2.sup.n pairs of n-bit input numbers and each of the 2.sup.n pairs of n-bit output numbers in the third table, to (n+1)-bit numbers.